Annual report pursuant to Section 13 and 15(d)

Goodwill - Schedule of Changes in Goodwill (Detail)

v3.19.1
Goodwill - Schedule of Changes in Goodwill (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Goodwill [Line Items]    
Balance, beginning of period before cumulative loss on impairment $ 28,453 $ 27,642
Beginning Balance, Accumulated loss on impairment (2,029) (2,029)
Balance, beginning of period after cumulative loss on impairment 26,424 25,613
Balance, end of period before cumulative loss on impairment 28,818 28,453
Ending Balance, Accumulated loss on impairment (2,029) (2,029)
Ending period balance 26,789 26,424
Radio Stations [Member]    
Goodwill [Line Items]    
Acquisitions 7 14
Goodwill, Written off Related to Sale of Business Unit (628)  
Digital Media [Member]    
Goodwill [Line Items]    
Acquisitions $ 986 810
Broadcast Business [Member]    
Goodwill [Line Items]    
Goodwill, Written off Related to Sale of Business Unit   $ (13)